Move the base Context stuff to another module to keep context free for imports.

jedi/api/interpreter.py

@@ -2,10 +2,10 @@
 TODO Some parts of this module are still not well documented.
 """
 
-from jedi.evaluate.context.module import ModuleContext
+from jedi.evaluate.context import ModuleContext
 from jedi.evaluate import compiled
 from jedi.evaluate.compiled import mixed
-from jedi.evaluate.context import Context
+from jedi.evaluate.base_context import Context
 
 
 class NamespaceObject(object):